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Amorphous Iridium Oxide-Integrated Anode Electrodes with Ultrahigh Material Utilization for Hydrogen Production at Industrial Current Densities

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Nano-Micro Letters 2024年第10期16卷 225-239页

作者： Lei Ding Kui Li Weitian Wang Zhiqiang Xie Shule Yu Haoran Yu David ACullen Alex Keane Kathy Ayers Christopher BCapuano Fangyuan Liu Pu-Xian Gao Feng-Yuan Zhang Department of Mechanical Aerospace and Biomedical EngineeringUniversity of TennesseeKnoxvilleTN 37996USA Oak Ridge National Lab Center for Nanophase Materials SciencesOak RidgeTN 37831USA Nel Hydrogen WallingfordCT 06492USA Institute of Materials Science University of ConnecticutStorrsCT 06269USA Department of Materials Science and Engineering University of ConnecticutStorrsCT 06269USA

Herein,ionomer-free amorphous iridium oxide(IrO_(x))thin electrodes are first developed as highly active anodes for proton exchange membrane electrolyzer cells(PEMECs)via low-cost,environmentally friendly,and easily scalable electrodeposition at room *** with a Nafion 117 membrane,the IrO_(x)-integrated electrode with an ultralow loading of 0.075 mg cm^(-2)delivers a high cell efficiency of about 90%,achieving more than 96%catalyst savings and 42-fold higher catalyst utilization compared to commercial catalyst-coated membrane(2 mg cm^(-2)).Additionally,the IrO_(x)electrode demonstrates superior performance,higher catalyst utilization and significantly simplified fabrication with easy scalability compared with the most previously reported ***,the remarkable performance could be mainly due to the amorphous phase property,sufficient Ir^(3+)content,and rich surface hydroxide groups in ***,due to the high activity,high cell efficiency,an economical,greatly simplified and easily scalable fabrication process,and ultrahigh material utilization,the IrO_(x)electrode shows great potential to be applied in industry and accelerates the commercialization of PEMECs and renewable energy evolution.

关键词： Ionomer-free Amorphous IrOx electrodes Ultrahigh material utilization Scalable electrodeposition Hydrogen production

Nano-enhanced solid-state hydrogen storage:Balancing discovery and pragmatism for future energy solutions

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Nano Research 2024年第10期17卷 8729-8753页

作者： Chaochao Dun Xinyi Wang Linfeng Chen Sichi Li Hanna M.Breunig Jeffrey J.Urban The Molecular Foundry Lawrence Berkeley National Laboratory BerkeleyBerkeleyCA 94720USA Energy Analysis and Environmental Impacts Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Lawrence Livermore National Laboratory LivermoreCA 94550USA

Nanomaterials have revolutionized the battery industry by enhancing energy storage capacities and charging speeds,and their application in hydrogen(H_(2))storage likewise holds strong potential,though with distinct challenges and mechanisms.H_(2) is a crucial future zero-carbon energy vector given its high gravimetric energy density,which far exceeds that of liquid ***,its low volumetric energy density in gaseous form currently requires storage under high pressure or at low *** review critically examines the current and prospective landscapes of solid-state H_(2) storage technologies,with a focus on pragmatic integration of advanced materials such as metal-organic frameworks(MOFs),magnesium-based hybrids,and novel sorbents into future energy *** materials,enhanced by nanotechnology,could significantly improve the efficiency and capacity of H_(2) storage systems by optimizing H_(2) adsorption at the nanoscale and improving the kinetics of H_(2) uptake and *** discuss various H_(2) storage mechanisms—physisorption,chemisorption,and the Kubas interaction—analyzing their impact on the energy efficiency and scalability of storage *** review also addresses the potential of“smart MOFs”,single-atom catalyst-doped metal hydrides,MXenes and entropy-driven alloys to enhance the performance and broaden the application range of H_(2) storage systems,stressing the need for innovative materials and system integration to satisfy future energy ***-throughput screening,combined with machine learning algorithms,is noted as a promising approach to identify patterns and predict the behavior of novel materials under various conditions,significantly reducing the time and cost associated with experimental *** closing,we discuss the increasing involvement of various companies in solid-state H_(2) storage,particularly in prototype vehicles,from a techno-economic *** forward-looking perspective underscores t

关键词： nanomaterials nanotechnology solid-state H_(2)storage techno-economic analysis model-driven material development processes

Current challenge and perspective of PGM-free cathode catalysts for PEM fuel cells

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Frontiers in Energy 2017年第3期11卷 286-298页

作者： Gang WU Department of Chemical and Biological Engineering University at Buffalo The State University of New York Buffalo New York 14260 USA

To significantly reduce the cost of proton exchange membrane fuel cells, platinum-group metal （PGM）-free cathode catalysts are highly desirable. Current M-N-C （M： Fe, Co or Mn） catalysts are considered the most promising due to their encouraging performance. The challenge thus has been their stability under acidic conditions, which has hindered their use for any practical applications. In this review, based on the author＇s research experience in the field for more than 10 years, current challenges and possible solutions to overcome these problems were discussed. The current Edisonian approach （i.e., trial and error） to developing PGM-free catalysts has been ineffective in achieving revolutionary breakthroughs. Novel synthesis techniques based on a more methodolo- gical approach will enable atomic control and allow us to achieve optimal electronic and geometric structures for active sites uniformly dispersed within the 3D architec- tures. Structural and chemical controlled precursors such as metal-organic frameworks are highly desirable for making catalysts with an increased density of active sites and strengthening local bonding structures among N, C and metals. Advanced electrochemical and physical characterization, such as electron microscopy and X-ray absorption spectroscopy should be combined with first principle density functional theory （DFT） calculations to fully elucidate the active site structures.

关键词： oxygen reduction fuel cells cathode non- precious metal catalysts carbon nanocomposites

Dependence of interface energetics and kinetics on catalyst loading in a photoelectrochemical system

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Nano Research 2019年第9期12卷 2378-2384页

作者： Yumin He Srin ivas Vanka Tianyue Gao Da He Jeremy Espano Yanyan Zhao Qi Dong Chaochao Lang Yongjie Wang Thomas W. Hamann Zetian Mi Dunwei Wang Department of Chemistry Merkert Chemistry CenterBoston College2609 Beacon StreetChestnut HillMassachusetts 02467USA Department of Electrical Engineering and Computer Science University of Michigan1301 Beal AvenueAnn ArborMichigan 48109USA Department of Chemistry Michigan State UniversityEast LansingMichigan 48824USA Department of Electrical and Computer Engineering McGill University3480 University StreetMontrealQuebecH3A 0E9Canada

Solar hydrogen production by the photoelectrochemical method promises a means to store solar *** it is generally understood that the process is highly sensitive to the nature of the interface between the semiconductor and the electrolyte,a detailed understanding of this interface is still *** instance,few prior studies have established a clear relationship between the interface energetics and the catalyst loading *** we aim to study this relationship on a prototypical Si-based photoelectrochemical *** types of interfaces were examined,one with GaN nanowires as a protection layer and one *** was found that when GaN was present,higher Pt loading (> 0.1 μg/cm2) led to not only better water reduction (and,hence,hydrogen evolution) kinetics but also more favorable interface energetics for greater *** the absence of the protection layer,by stark contrast,increased Pt loading exhibited no measurable influence on the interface energetics,and the main difference was observed only in the hydrogen evolution *** study sheds new light on the importance of interface engineering for further improvement of photoelectrochemical systems,especially concerning the role of catalysts and protection layers.

关键词： photoelectrochemistry water splitt ing Si hydroge n evolutio n catalyst nano wires

Mixed ion and electron transport theory and application in solid oxide conductors

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 870-875页

作者： Kevin Huang Department of Mechanical engineering University of South CarolinaColumbiaSC 292201USA

Mixed ions and electron conductors(MIECs)are an important family of electrocatalysts for electrochemical devices,such as reversible solid oxide cells,rechargeable metal-air batteries,and oxygen transport *** ionic and electronic transports in these materials play a key role in electrocatalytic *** in-depth fundamental understanding of the transport phenomena is critically needed to develop better *** this brief review,we introduced generic ionic and electronic transport theory based on irreversible thermodynamics and applied it to practical oxide-based materials with oxygen vacancies and electrons/holes as the predominant *** oxide systems,namely CeO_(2)-based and La CrO_(3)-based materials,are selected as case studies to illustrate the utility of the transport theory in predicting oxygen partial pressure distribution across MIECs,electrochemical electronic/ionic leakage currents,and the effects of external load current on the leakage currents.

关键词： irreversible thermodynamics diffusivity charge neutrality electrochemical potential electrostatic potential

High-performance oxygen reduction catalysts in both alkaline and acidic fuel cells based on pre-treating carbon material and iron precursor

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Science Bulletin 2017年第23期62卷 1602-1608页

作者： Ping Song Heather M.Barkholtz Ying Wang Weilin Xu Dijia Liu Lin Zhuang State Key Laboratory of Electroanalytical Chemistry Jilin Province Key Laboratory of Low Carbon Chemical Power Changchun Institute of Applied ChemistryChinese Academy of Sciences Chemical Sciences and Engineering Division Argonne National Laboratory College of Chemistry and Molecular Sciences Hubei Key Laboratory of Electrochemical Power Sources Wuhan University

We demonstrate a new and simple method for pre-treating the carbon material and iron precursor to prepare oxygen reduction reaction(ORR) catalysts, which can produce super-high performance and stability in alkaline solution, with high performance in acid solution. This strategy using cheap materials is simply controllable. Moreover, it has achieved smaller uniform nanoparticles to exhibit high stability, and the synergetic effect of Fe and N offered much higher performance in ORR than commercial Pt/C, with high maximum power density in alkaline and acid fuel cell test. So it can make this kind of catalysts be the most promising alternatives of Pt-based catalysts with best performance/price.

关键词： Pre-treatment Uniform nanoparticle Super-high performance High stability fuel cell

Electrochemically Grown Ultrathin Platinum Nanosheet Electrodes with Ultralow Loadings for Energy-Saving and Industrial-Level Hydrogen Evolution

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Nano-Micro Letters 2023年第9期15卷 257-274页

作者： Lei Ding Zhiqiang Xie Shule Yu Weitian Wang Alexander Y.Terekhov Brian K.Canfield Christopher B.Capuano Alex Keane Kathy Ayers David A.Cullen Feng-Yuan Zhang Nanodynamics and High-Efficiency Lab for Propulsion and Power Department of MechanicalAerospace&Biomedical EngineeringUT Space Institute(University of Tennessee-Knoxville)TullahomaTN 37388USA Center for Laser Applications UT Space Institute(University of Tennessee-Knoxville)TullahomaTN 37388USA Nel Hydrogen WallingfordCT 06492USA Oak Ridge National Laboratory Center for Nanophase Materials SciencesOak RidgeTN 37831USA

Nanostructured catalyst-integrated electrodes with remarkably reduced catalyst loadings,high catalyst utilization and facile fabrication are urgently needed to enable cost-effective,green hydrogen production via proton exchange membrane electrolyzer cells(PEMECs).Herein,benefitting from a thin seeding layer,bottom-up grown ultrathin Pt nanosheets(Pt-NSs)were first deposited on thin Ti substrates for PEMECs via a fast,template-and surfactant-free electrochemical growth process at room temperature,showing highly uniform Pt surface coverage with ultralow loadings and vertically well-aligned nanosheet *** with an anode-only Nafion 117 catalyst-coated membrane(CCM),the Pt-NS electrode with an ultralow loading of 0.015 mgPt cm−2 demonstrates superior cell performance to the commercial CCM(3.0 mgPt cm^(−2)),achieving 99.5%catalyst savings and more than 237-fold higher catalyst *** remarkable performance with high catalyst utilization is mainly due to the vertically well-aligned ultrathin nanosheets with good surface coverage exposing abundant active sites for the electrochemical ***,this study not only paves a new way for optimizing the catalyst uniformity and surface coverage with ultralow loadings but also provides new insights into nanostructured electrode design and facile fabrication for highly efficient and low-cost PEMECs and other energy storage/conversion devices.

关键词： Seeding layer Electrochemically grown Pt nanosheet Ultralow loadings High catalyst utilization Hydrogen evolution

Electrocatalysts development for hydrogen oxidation reaction in alkaline media:From mechanism understanding to materials design

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Chinese Journal of Catalysis 2021年第12期42卷 2094-2104页

作者： Yang Qiu Xiaohong Xie Wenzhen Li Yuyan Shao Pacific Northwest National Laboratory RichlandWashington 99352USA Department of Chemical&Biological Engineering Iowa State UniversityAmesIAUSA DOE’s Ames Laboratory AmesIAUSA

Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as ***,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders of magnitude slower in alkaline systems than in *** understand the slower kinetics of HOR in base,two major theories have been proposed,such as(1)pH dependent hydrogen binding energy as a major descriptor for HOR;and(2)bifunctional theory based on the contributions of both hydrogen and hydroxide adsorption for HOR in alkaline ***,we discuss the possible HOR mechanisms in alkaline electrolytes with the corresponding change in their Tafel *** from the traditional Tafel-Volmer and Heyrovsky-Volmer HOR mechanisms,the recently proposed hydroxide adsorption step is also discussed to illustrate the difference in HOR mechanisms in acid and *** further summarize the representative works of alkaline HOR catalyst design(e.g.,precious metals,alloy,intermetallic materials,Ni-based alloys,carbides,nitrides,etc.),and briefly describe their fundamental HOR reaction mechanism to emphasize the difference in elementary reaction steps in alkaline *** strategy of strengthening local interaction that facilitates both H2 desorption and Hads+OHads recombination is finally proposed for future HOR catalyst design in alkaline environment.

关键词： Hydrogen oxidation reaction Alkaline electrolyte fuel cell Electrocatalyst Electrocatalysis Hydrogen and hydroxide binding energy

PGM-Free Oxygen-Reduction Catalyst Development for Proton-Exchange Membrane fuel cells:Challenges,Solutions,and Promises

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Accounts of Materials Research 2022年第2期3卷 224-236页

作者： Yanghua He Gang Wu Department of Chemical and Biological Engineering University at BuffaloThe State University of New YorkBuffaloNew York 14260United States

CONSPECTUS:Proton-exchange membrane fuel cells(PEMFCs)are efficient and clean hydrogen energy technologies for transportation and stationary *** active and durable low-cost cathode catalysts for the oxygen-reduction reaction(ORR)under challenging acidic environments are desperately needed to address the cost and durability issues of *** most promising platinum group metal(PGM)-free catalysts for the ORR in acidic media are atomically dispersed and nitrogencoordinated metal site catalysts denoted as M−N−C,M=Fe,Co,or *** to significant efforts in the past few decades,these catalysts have demonstrated much-improved ORR activity and promising initial fuel cell performance approaching traditional Pt/C ***,the insufficient long-term stability(up to 5000 h)under PEMFC operation represents a primary technical barrier to making current PGM-free catalysts less viable yet in *** this Account,we highlight recent advances in synthesizing efficient PGM-free catalysts for the ORR in PEMFCs,emphasizing effective strategies to improve mass and intrinsic activity and the possible degradation *** particular,a chemical doping method based on the zeolitic imidazolate framework(ZIF)-8 represents the key to developing efficient M−N−C catalysts containing atomically dispersed and nitrogen-coordinated single metal active sites(i.e.,MN_(4)).The newly acquired understanding of the formation mechanism of MN_(4)active sites during the thermal activation and its correlation to catalytic properties guide the rational catalyst design rather than relying on current trial-and-error *** efforts have further been invested in increasing the active site density and enhancing intrinsic activity by regulating carbon-phase structures and the local coordination *** highly active catalysts usually suffer from significant activity loss during the ***,breaking the activity−stability trade-off is the key to simul

关键词： catalyst Oxygen durability